The Witcher 2: Can't find the Kayran Skin?

Hey I just discovered the formula for creating the kayran skin armour in my inventory. The thing is once I defeated the boss I forgot to loot his corpse. If I go back to the place where I killed him will he still be there? Also, I can't seem to find the route to where I killed him, all I remember is that it was a wide field looking area. Can I just buy the kayran skin? thanks :D